Sleep deprivation makes you more sensitive to pain.
A study in the April 2009 issue of Sleep Journal showed that normal, healthy individuals are more sensitive to pain when they are low on rest. The reasons why aren’t known for sure. “Some research studies show that sleep deprivation causes increased production of inflammatory chemicals in the body called cytokines,” Marks says.
Pain medications interrupt sleep. Unfortunately, some of the medications prescribed for pain, such as codeine and morphine, can cause insomnia. These opioid pain medications can cause apnea, brief pauses in breathing, during sleep. “Therefore, people who take these kinds of medications for chronic pain are at a higher risk for sleep problems,” Falco says.
People with chronic pain may have trouble exercising. Lack of exercise leads to weight gain. Excess weight then restricts exercise, which leads to more pounds gained. “This vicious cycle can lead to sleep apnea, which prevents a restful night’s sleep,” Falco says.
Different Types of Pain
According to the National Sleep Foundation, the types of pain that most commonly cause insomnia are back pain; headaches; and temporomandibular joint (TMJ) syndrome, which causes pain around the ears and jaw muscles. Muscoloskeletal pain, including arthritis and fibromyalgia, can also cause sleep problems. Cancer pain, resulting from the disease itself and treatment, also leads to trouble sleeping. Pain that follows surgery can also prevent much-needed rest.
As Falco points out, current research shows that there are more commonalities than differences between types of pain when it comes to insomnia. A few of the nuances researchers have identified include the following:
- The intense nature of pain after surgery and other acute pain seems to affect both the length and quality of sleep.
- Chronic arthritis pain appears to interfere with circadian rhythms. A recent Japanese study found a relationship between a person’s body clock and arthritis symptoms. More specifically, researchers discovered that certain genes affecting circadian rhythms may activate a molecule that sparks inflammation in people with arthritis. The relationship between this molecule, called TNF-alpha, and circadian rhythms may explain why people with arthritis have worse joint pain in the morning.
- In people with fibromyalgia, a chronic condition that causes joint and muscle pain, there are constant bursts of “awake” brain activity which prevents deep sleep. In a study published in the Journal of Rheumatology, people with fibromyalgia had two times as many awakenings per hour as people without the disease.